Cost: -80% (base)
One-Spell Magery is a limitation on Magery where any levels of magery limited this way only act in respect to that spell. It assumes that Unusable Prerequisites is being used. The No Prerequisites Needed (+30%) enhancement must be added to eliminate this requirement.
Derivatives[]
For magery with more then one spell remove -5% per spell after the first; e.g., four-spell Magery would be -65%. Past a certain point it make more sense from a cost stand point to get Limited College (One) instead.
Average spells[]
IQ/A spells from Magic: The Least of Spells don't require magery to cast in normal mana (only low mana) so there is less incentive to buy one-spell magery for them.
Racial skill bonuses[]
These can be up to +3 to a skill at 2 points per level. This happens to be the same that one-spell magery costs.
Differences being that RSBs cannot be stolen by spells, do not increase possible effect, don't add to roll to sense that spell in an item
Insights[]
Prereqs[]
Since the limitation says nothing about eliminating spell prerequisites it follows this is more like the old Divination Talent where it did not "replace prerequisites, which must still be learned (but may not be cast unless the diviner is in a high-mana area or is a mage)". This view is supported by the way Racially Innate Spells are priced (-40%) which seems to include No Spell Prerequisites (+30%).
Cost[]
Since this reduces the cost of raising a spell by 1 point to 2 character points, it effectively means that a character should only ever put 1 point in any spell, since Magery gives additional benefits besides the effective +1 to IQ.
It probably balances better with the Ritual Magic system where spells are merely techniques, and cheaper to buy up (1 point per 1 point) since then even single-spell magery would always be more expensive.
Of course, magery actually becomes less important using that system, since you can simply buy up the base skill (like thaumatology) more cheaply a 4/level instead of 10/level.
However, given Special Case for Magery 0 this limitation must be applied to Magery 0. This is because Magery 0 with no modifiers allows one to learn every spell that doesn't require Magery 1+ in the setting under the standard magic system.
Different Number of Colleges[]
The cost of Limited Colleges is derived from One-College Magery (-40%) which its based there being 15 to 30 available colleges. For different numbers of colleges it changes value. It logically follows that the number of Colleges will also change the base for One-Spell Magery and Limited Spell List. Combining the rules produces this table (green cells are given in rules, the rest are extrapolated). It will be noted that while capped at (-80%) the same number of spells needed to "break-even" remains the same (9) because this calculation uses One-Spell Magery's actual value of (-100%).
| Total Colleges in setting | 2 | 3 to 2 | 7 to 14 | 15 to 30 | 30+ |
|---|---|---|---|---|---|
| One-College Magery | (-10%) | (-20%) | (-30%) | (-40%) | (-60%) |
| Limited Spell List Cost | NA | (-10%) | (-20%) | (-30%) | (-50%) |
| One-Spell Magery Base Cost | (-50%) | (-60%) | (-70%) | (-80%) | (-80%) cap (-100%) actual |
References and Notes[]
- GURPS Thaumatology pg 25
- GURPS Fantasy pg 129 talks about how this intersects with Hyperdivided Magery.